from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Wearing a poker face: studiously neutral; giving nothing away.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. deliberately impassive in manner
From the attitude necessary in the game of poker, since one is ill-advised to reveal delight at being dealt a winning hand lest other players decline to bet (or contrariwise, show disappointment at a poor hand if one is inclined to bluff). (Wiktionary)